Volume 4, Issue 2 (March 1976)

Yield Point Standardization

The yield point, that is, the stress at which a steel starts to suffer a pronounced permanent set, is a very important property. There is in international standardization a dilemma about whether to use upper yield point (ReH) or lower yield point (ReL) as the characterizing yield point value in steel standards and in practical material testing. This dilemma may to a great extent be due to the people involved in standardization themselves exaggerating the difference between ReH and ReL. Both yield point values are dependent on the strain rate, which again may be greatly influenced by the compliance of the testing system. Some confusion may exist regarding the term “upper yield point” as compared with the term “yield point.”